Thermopile



ma, 2, w43., F. R. HJIGLEY 2,310,025

THERMOPILE Fild Nov. 14, 1940 IL 5 a? INVENTOR.

'fQ/KE-Mc-MEY ATTORNEYS t. t t n. igley, Clevelan energias, om,assignorto The Bryant Heater Company, Cleveland,

Ohio, a corporation of Ohio application November 14, 1940, senatvantistatic a (ci. 'ies- 4) invention relates Vto improvements inthermopiles, and has reference to a novel construction of thermope aswell as to amethod oi making the same.

In control apparatus thermopiles areused to operate switches or valves;The current that may be set up by any one couple is of course quitesmall, and in order to build up a potential of sumcient amount a seriesof couples must be combined to give an additive result.4 The cost ofsuch a thermopile as heretofore constructed has been high, and that facthas-tended to limit `the number of couples to whateveris found to beabsolutely essential. 4 I

The present invention seeks to provide a thermopile ofany requirednumber of couples at a relatively lowcost, and one in which theapplication of heat to the hot junctions may be accom- Iplished easilyand eiiiciently.

The primary object of the invention therefore is the provision of .a lowcost high efliciency thermopile. I i

Another object is the provision of a novel thermopile mounting,particularly adaptable to control mechanism for gas burners or the like.

Other objects and features of novelty will appear as I proceed with thedescription `of those embodiments of the invention which, lfor thepurposes of the present application, I have illustrated in theaccompanying drawing, in which Fig.-1 is an'elevational view of athermopile constructed in accordance with the invention.

Fig. 21s an end view of the same.

Fig. 3 is an elevational view partly broken away and partly in sectionillustrating another embodiment of the invention.

Fig. i is an end view of the same partly in elevation and partly' insection.

, Fig. 5 is a top plan view of a further modification of the invention.

Fig. 6 is an elevational view, partly in vertical section, of theconstruction shown in Fig. 5.

Fig. 'i is a view similar to Fig. 6 of a slightly I modified form of theinvention.

4termed.. Various metals or alloys may be usedl for the wire coil, andvarious metals may be used for the coating on the coil. As examples ofsuch that the repeated expansions and contractions due totemperaturechanges may not affect adversely the adherence of the coating to thewire. The application of the coating to the wire may fbe eected byplating, dipping. spraying, etc. I

prefer however to plate it onto the wire. The

wire after being formed into a coil of the length Iand diameterI desiredmay be immersed p'art-vvay in a platingbath. Preferably one-half of thecoil is immersed and this half is plated, so that after the coil isremoved from the plating bath one-half of each convolution is plain wireand the other half is coated wire, and the two Junctionsbetween thecoated and uncoated portions of each convolution are spaced preferably180 apart.

When the plating, or coating by other method,

has been completed and the coil has been removed from the coatingapparatus, it may be permitted to remain straight, as in Figs. 1 to 4inclusive, or Vit may be ,bent into a ring as in Figs. 5, 6 and 7.Referring first to Figs.'1 and 2, one set of junctions between the partsI 0 4and II is in this case joined mechanically but not electrically bya pair of bars I2 and I3 that are held together by high temperaturecement 9, which also serves.`

to rmly fix the convolutions in properly spaced relation and to transmitheat to the junctions.

Heat is applied to one of these bars by names I! or other suitablemeans.' The bars I2 and I3 are made of some non-metallic refractorymaterial which is not a conductor of electricity, for example porcelainor oven glass.-

In the form of the invention illustrated in Figs. 3 and 4 the straightcoil is arranged with one set of junctions at Vthe top and the other setat the bottom, and a tubular fluid fuel burner I5 is introduc'ed'intothe coil with the burner openings in a row at the top thereof. When theburner is on the flames heat the junctions above them.

materials I may mention a ferrous alloy as the Furthermore the draftcreated by the heat from the flames causes a ow of cool air upwardlyover the lower set of junctions which helps to maintain a widedifference in temperature between the upper and lower sets of junctions.In order to accentuate this eiIect I may partially enclose the coi1 in anon-metallic refractory electrical insulation material it providing anopentopped housing' with an alr passage I1 beneath the lower set ofjunctions, so that the air now induced by the natural draft is connedsomewhat and caused to pass over the lower junctions. Wnere a thermopileof this design is used in control apparatus for gas burners the tube I5may be continued beyond one end of the coil where it may be providedwith a larger orifice in order to function as the pilot of the system.

In the construction. oi.' Figs. 5 and 6 the coil after being coated inlthe same manner as before is bent into a hollow ring, each convolutionhowever being separated from adjacent convolutions by an air space orother electric insulating medium. The coated portions ofthe convolutionsin this instance are positioned at the top of the coil in order that oneset of junctions may fall at the inner border of the ring and the otherset at the periphery of the ring. The coil then may be associated with apilot or other burner I8 adapted to play a flame upon all of the innerjunctions.

Instead of directing a flame against the inner junctions in the ringform of the device, the inner portions of the convolutions may be sprunginto an annular recess I9 in a porcelain or other heat conducting andelectric insulating post 2U, the inner junctions then being heated byconduction from a flame 2l which is directed against the post at a pointsomewhat removed from the wire coil. Care must be taken as before tomaintain the inner parts of the convolutions electrically separated.

While as previously stated the coating of the wire coil may beaccomplished in diierent ways, the procedure which I prefer at `thepresent time is electroplating. Apparatus which may be employed in thisstep of the method is illustrated schematically in Fig. 8 where 22 is atank containing electrolyte 23. 24 represents an anode of chromium,nickel, silver or other metal which it is desired to deposit upon thecoil. 25 is a combination support and conductor which is caused toextend through the coil from end to end and is then rested upon oppositewalls of the tank. The coil then hangs down into the electrolyte whichis maintained at a level such that approximately half of the coil isimmersed. 26 and 21 represent electric conductors for transmitting acurrent of electricity into and through the apparatus. It will beobvious that by the Patent No. 2,510,026.

FRANK4 R. HIGLEY.

operation of this apparatus the desired coatingmay be applied to thedesired portion of the coil, generally one-half of the same.

Having thus described my invention, I claim:

1. A method of making a thermopile which comprises helically coiling alength of wire, coating one longitudinal halt of said coil with a metaldifferent from that of the wire to form two junctions of coated anduncoated wire approximately apart for each convolution of the coil.'bende ing the coil either before or after the application of the coatingto form a hollow ring with corresponding junctions at the inner borderof the ring and providing means for applying heat to said last namedjunctions. the remaining portions of the convolutions being left freeand unobstructed to facilitate the rapid dissipation of heat.

2. In a thermopile, a torus comprising a helical 'coil of metal wirehaving circular hollow' convolutions, a coating of a different metal ononehalf of each convolution, the coated and uncoated portions oi. theconvolutions lying upon opposite sides of a plane through the centers oithe convolutions, whereby one set of Junctions between coated anduncoated portions are arranged .in the inner circle of the torus, andmeans for applying heat to said set of junctions.

3. In a thermopile, a helical coil of metal Wire bent to the form of atorus, a coating of a different metal on one-half of each convolution.the coated and uncoated portions of the convolutions lying upon oppositesides of a plane through the centers of the convolutions, whereby oneset of junctions between coated and uncoated portions is arranged in theinner circle of the torusl and an electric insulator and heat conductorengaging the junctions at the said inner circle of the torus.

4. In a thermopile, a torus comprising a helical coil of metal wirehaving circular hollow con volutions, a coating of a different metal ononehalf of each convolution, the coated and uncoated portions of theconvolutions lying upon opposite sides of a plane through the centers ofthe convolutions, whereby one set of junctions between coated anduncoated portions is arranged in the inner circle of the torus, and aheat conducting post of electrical insulation resiliently mounted in theinner circle of the torus.

FRANK R. HIGLEY.

CERTIFICATE or coautorfor.4 f

February '2, 191e.

oftgibhereby certified thai-.error appears in the 'printed3specification ond- .ove numbered patent requiring correction as follows:Page 2 secmo glum, -lines 29 and 5o, Claims, rerthe -woz-esseci come *Ineither?V4 pl a helical coil ofI metal wire bent to the form of a torusread 4 In e. thermopile, a'torus comprising e. helical coil yof metalwire-ha lrllg r'ular hollow ,eonvolutions,;v and that .the said 'LettersPatert s ou streed with' this' o the record of' the 129.89inctlri'ettxel.that the *same mgy enfom to ysigned and sealed this 415th.day er April, lr.' D. 1915.

Henry van Andale,

. CERTIFICATE oF conmzc'-rrq1r.v 'Patent No. 2,510,026. I Eebmmjg.191,15. FRAM; n. Hmmmg L It .is hereby' certified thefterror appears inthe printed' specification' of the above nnmbered patent redul'ringcorrection as follows: Pege 2, seci 0nd column, lines 29 and 50, claim,furthe wordaand comm. 'In a thermopile,a helical coil oif'metal wirebent tothe forgn of a torus]I vread ing'circular hcllow c0nvo1ut1ons,;and that .the .said 'Letters Patent should beregdwith' this correctiontherein that the same mey conform to the record of the cese' inthe'Pat-ent Office. v l

eigned and sealed this ,15th .any f April, A D. 1915.

- I Henry van Arsdle, (Seal) Acting Commissioner` of Patents.

